BIO 181 Exam 2
What do you contact-dependent signaling and paracrine signaling have in common?
Cells release a signal that affects neighboring cells
Plant cell walls contain _______.
Cellulose
________ is a polymer of glucose
Cellulose
What structure easily distinguishes a plant cell from an animal or bacterial cell?
Chloroplasts, nucleus, and Golgi apparatus
In Barrow, Alaska, the sun does not set for several months in the summer. Based on what you know about photoperiodism, what type of plant is most likely to flower during the summer in Barrow?
Day-neutral plants
True or false: A dehydration reaction that builds larger molecules from smaller units requires the addition of a water molecule
False
True or false: Osmosis describes the movement of water from an area of HIGH to LOW solute concentration
False
True or false: Saturated fats are composed of fatty acids with several double bonded carbons
False
True or false: Vertical evolution, whereby living organisms evolve from a common ancestor ("tree of life"), is the only mechanism of evolution on Earth.
False
With an atomic mass of 16 and an atomic number of 8, it follows that oxygen
- has eight electrons. - can readily form bonds with 2 other atoms.
If a persons ability to form steroids in their body was destroyed, what function would be affected?
1. Molecular hydrolysis reactions would stop functioning 2. Estrogen would no longer be produced in the body 3. Cholesterol levels would keep increasing causing cell death
How might a plant cell compensate for the excessive membrane fluidity that occurs during prolonged exposures to elevated temperature?
Alter the lipid composition to have longer phospholipid tails and fewer double bonds.
Which of the following are physical stimuli that influence plant responses?
CO2, light, water vapor, gravity
What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+ concentration)?
Calcium movement involves active transport
Eukaryotes differ from prokaryotes, in part because eukaryote cells
Have a membrane-bound nucleus
In the process of biological evolution, new species may evolve through exchange of genes from one species to another is called
Horizontal gene transfer
What type of bonding is likely to occur between two water molecules or strands of DNA?
Hydrogen
The strongest chemical bonds are
covalent bonds
Cyanide binds and impairs one of the molecules involved in the synthesis of ATP. The target organelle for cyanide must be
Mitochondria
Sickle cell anemia is a condition in which red blood cells exhibit a characteristic "sickle" shape. This arises from a mutation or change in one of the amino acids found in hemoglobin. A single amino acid mutation would directly affect a proteins _______ structure
Primary
A cell wall is present in
Prokaryotic and plant cells
Large number of ribosomes are present in Eukaryotic cells that produce
Proteins
A substrate binding to an enzyme is most similar to a signal molecule binding to a
Receptor
The best way to describe cellular membrane is
Semi fluid with lipid rafts
The portion of an amino acid that makes it unique among the 20 different amino acids is its
Side-chain or R group
Diabetics can be given insulin that binds to receptors on cells throughout the body increasing glucose uptake. Insulin is an example of a
Signal
The gonads produce steroids. The specific steroid-producing organelles in gonad cells are
Smooth Endoplasmic Reticulum (Smooth ER)
Roots contain starch-heavy plastids known as:
Statoliths
The subunits (monomers) sometimes build up to form a macromolecule (polymers). Which is NOT a monomer of a polymer
Steroid
The movement of sucrose and H+ into the cell by the same membrane protein reflects the actions of what type of transporter?
Symporter
In some cases, just a few hormone molecules binding to the surface of a cell can trigger a very large response because
The signal is amplified by activation of enzymes that each catalyze multiple reactions
True or false: A community is composed of different populations of animals and plants.
True
True or false: Plant behavior is defined as response to stimuli.
True
True or false: The primary structure of a protein Ultimately determines its three-dimensional structure
True
True or false: Whether a signaling molecule operates locally or over long distances, it must bind to a specific receptor to elicit a cellular response
True
The function of a cell is related to the amount of surface area it has. Is this statement true or false and why?
True. A cell with the same mass can increase surface area with structures like microvilli that enhance absorption functions
The production of second messengers in signal transduction offers at least two advantages, speed and
amplification
Fats and fatty acids...
are insoluble in water
In the periodic table, the value that refers to the number of protons and neutrons is
atomic mass
For water to vaporize
both energy must be supplied and hydrogen bonds broken
The addition of a strong acid like HCl to an aqueous solution would result in
both the release of H+ and a decrease in pH
Which level of organization is common to all life forms?
cell
The organelle responsible for the biosynthesis of proteins that are destined for secretion by the cell is the
endoplasmic reticulum
Following a meal, glucose must move from the gut lumen where there is a high glucose concentration into the intestinal cell where there is a relatively low level of glucose. This movement is called
facilitated diffusion
A significant role played by pH buffers is to
limit major shifts in the amount of H+ and OH- in solution
The process that most involves the selective uptake of a specific cargo molecule into the cell through receptor binding and aggregation is
receptor-mediated endocytosis
Boa constrictor's on an island are an example of a
Population
The organelles most likely to have the ability to divide and reproduce themselves like a cell would be
Both mitochondria and chloroplasts
A cell responds to a signal it sent. This is an example of
Autocrine signaling
A cell secretes a growth factor that binds to receptors on its own membrane preventing it from proliferating. This is an example of:
Autocrine signaling
If the tight junctions in the intestines were disrupted
Bacteria could move from the intestines to the blood stream causing infection
The phenomenon through which populations of organisms change over several generations is termed
Biological evolution
A community of organisms interacting with their physical environment is an
Ecosystem
The nucleus is to eukaryotes as the ________ is to prokaryotes
Nucleoid
An amino acid is to a protein as a _______ is to a nucleic acid
Nucleotide
The LEAST hydrophilic substance is
Oil
A cell secretes a growth factor that binds to receptors on neighboring cells causing them to proliferate. This is an example of:
Paracrine signaling
For heart muscles to beat in a coordinated rhythm ions must move from one cell to the next through _______
gap junctions
During a period of low water availability, the prokaryotic structure that would protect a cell from desiccation (drying out) is the
glycocalyx
Gravitropism is defined as:
growth in response to the force of gravity
How does a macrophage (immune cell) consume a bacteria?
phagocytosis
Gap junctions in animal cells are most similar to ________ in plant cells
plasmodesmata
The nucleus of an atom is composed of
protons and neutrons
Sodium concentrations are higher outside and glucose concentrations are higher inside the cell. Using the same membrane protein for Na+ and glucose transport, what is it called when a Na+ electrochemical gradient is used to drive glucose transport into the cell against its concentration gradient?
secondary active transport
Which membrane component is most important for allowing large, charged molecules to pass through the membrane?
transmembrane proteins